Genetic studies shed light on white spot shrimp disease

SINGAPORE - Singapore scientists are gaining a clearer understanding of the shrimp viral disease White Spot Syndrome. They say it is a significant advance and will increase the understanding of how this economically devastating virus is genetically assembled and how it infects shrimp species.

Researchers at the National University of Singapore have confirmed that they have developed the most detailed list of DNA proteins involved in the virus produced so far.

White spot syndrome virus (WSSV) is a major pathogen that causes severe mortality and economic loss to shrimp cultivation worldwide. It is highly contagious disease and caused the virtual collapse of the Chinese shrimp farming industry in 1993. By 1995 the disease had spread to the United States.

The genome of WSSV contains a 305-kb double-stranded circular DNA. Now, the Singapore research team have shown the virus is assembled by at least 58 proteins.

Although it's not known how the proteins work together, their locality in the virus's genetic structure is shedding light on some of their functions and is expected to help determine which ones could be targeted by anti-viral drugs.

Clearer ID
Scientists are using shotgun identification of the structural Proteome of the virus. The technique has identified 45 viral proteins; 13 of them are reported for the first time. Previous gel-based proteomics studies on WSSV have identified 38 structural proteins.
Another technique, iTRAQ (isobaric tags for relative and absolute quantification), a quantitative proteomics strategy, has also been used to distinguish envelope proteins and nucleocapsid proteins of WSSV.

The latest results validated 15 previously identified structural proteins and their location, and a further 12 envelope proteins and two nucleocapsid proteins.

To date, the position of 42 structural proteins has been determined; 33 are envelope proteins, and nine are nucleocapsid proteins. This is a significant step, as it will advance studies into the assembly and mechanism of WSSV infection, say the researchers.

The studies are being conducted by : Zhengjun Li, Qingsong Lin, Jing Chen, Jin Lu Wu, Teck Kwang Lim, Siew See Loh, Xuhua Tang and Choy-Leong Hew at the Department of Biological Sciences, National University of Singapore